Valve.



T. M A. STEWART.

VALVE.

APPLICATION FILED JUNE 23, 1911.

1 1 32,88 Patented! Mar. 23, 1915.

THOMAS I/LCAVITY STEWART, OF MONTREAL, QUEBEC, CANADA.

VALVE.

Application filed J 11118 23, 1911.

. through the action of an overbalancing memher, valves constructedaccording to this invention being especially adapted for use inconnection with steam whistles or the like The invention has for itsobject to prov de a valve which will be positive in its action andgenerally to improve the construction ofvalves' of this type.

The invention may be said to consist of the construction, arrangementand combination of parts as hereinafter described and set forth in theclaim. 7

For full comprehension however of my invention reference will be had tothe accompanying drawings forming a part of this specification, in whichsimilar reference characters indicate the same parts and wherein:

Figure 1 is a sectional view of a valve constructed according to myinvention. Fig. 2 is a detail sectional view of the valve proper takenat right angles to Fig. 1 on the line 22 Fig. 1.

The valve casing is shown at 1 and is provided at one side with anintake port 2 adapted to be connected to a source of pressure fluidsupply and at its opposite side with an outlet opening 3 here shown ascommunicating with a steam whistle a portion of which is indicated atExtending between opposite walls of the valve casing and separating theintake and outlet parts from one another is a partition 5 having atapped opening 6 in which is screwed a. short sleeve 7 constituting thevalve seat upon which the main valve 8 seats. The valve 8 is providedwith a forwardly extending hollow stem which may comprise an interiorhollow member 9 integral with the valve and a sleeve 9 placed over thesaid member 9 and having a piston 10 formed integrally upon the forwardend thereof, this sleeve 9 being of smaller diameter than the interiorof the seat sleeve 7 to Specification of Letters Patent.

Patented Ma es, .1915.

Serial No.-634,936.

permit of passage of fluid when the valve 8 is lifted and having aseries of outwardly projecting ribs 9 whereby it is guided in the saidseat sleeve. The piston 10 extends into a short cylinder 11 the annularwall whereof forms an integral part of the valve casing while itsforward end is closed by a cap or plug 12. The combined length ofthe-sleeve 9 and piston 10 is less than the distancebetween theunderside of the valvew8wa-nd the inner end of the piston cylinder 11formed by the plug 12. This piston 10 is of larger area than that of thevalve 8 so that when fluidunder pressure is admitted to the spacebetweenthe piston and cap 12 the pressure on the piston will overbalancethe pressure on the valve and cause the latter to open. The extent towhich the valve opens maybe regulated by means of a screw 1'3 threadedinto a plug 13 screwed into a tapped open like is mounted in an annulargroove in the outside of the piston.

space in front of piston 10 is controlled by a pilot valve 15 locatedwithin the hollow stem 9 and seating in a seat 16 formed by acontraction of the passage therethrough, the valve having a forwardlyprojecting stem 17 which extends through the piston 10, cap 12- and asleeve 18 threaded into a tapped opening 19 in the latter, to a pointoutside the valve casing and in close proximity to the lever 20 pivotedas at 21 to the valve casing and provided with any suitable connectionwhereby it may be manually operated. The rear end of the valve 15extends to a point a short distance from a plug 13 screwed into a tappedopening in the front end of the main valve and having a longitudinalpassage 2:2 for the admission of fluid to the space, the fluid passingthence through an A spring 30, surrounding the stem 17 and bearing atopposite ends between the cap 12 and a pin 31 extending transverselythrough the stem, returns the valve 15 to its seat when the lever 20 isreleased.

Operation: To open the valve, lever 20 is depressed and the valve 15 islifted through the medium of stem 17, from its seat. The pressure fluidthen passes through passages 22, 23, 24, 25, 26, to the cylinder 11. The

pressure upon piston 10 overbalances the pressure on valve 8 and thelatter opens. When lever 20 is released the spring closes the valve 15when the slight leakage between the stem 17 and parts 11 (no packingbeing provided between these parts) and 18 allows the fluid to exhaustfrom the cylinder 11 and the valve 8 closes.

I claim In a valve, the combination with a casing having an inlet and anoutlet communicating with each other, a partition located between theinlet and outlet and having an opening therein, a main valve seat withinsaid opening and a piston cylinder formed in the casing, of a main valveadapted to be seated upon the main valve seat and having a tappedopening therein, a bored plug screwed into the opening in the mainvalve, an adjustable stop for limiting the opening movement of the mainvalve, such valve comprising a. hollow stem communicating with theopening in the valve and leading to the piston cylinder, an auxiliaryvalve seat formed in said hollow stem, a sleeve slidably mounted uponthe stem, engaging at one end with the underside of the main valve andhaving a piston head at its opposite end and located in and spaced fromthe inner end of said piston cylinder, such sleeve being of smallerdiameter than the interior of the main valve seat and having outwardlyprojecting ribs thereon, a closely fitting auxiliary valve located insaid hollow stem between the auxiliary valve seat and the bored plug,such auxiliary valve being reduced in diameter at a point above its seatand having a longitudinal passage therethrough and ports leading fromsuch passage to the exterior of the reduced portion of the valve, aloose fitting valve stem extending from the auxiliary valve to theexterior of the casing, a spring yieldingly holding the auxiliary valveupon its seat and means for opening the auxiliary valve against theinfluence of the spring.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

THOMAS IHOAVITY STEWART.

W'itnesses FRED J. S'IEARNS, ALBERT H. .BATCHELOR.

Copies of this patent may be obtained for five cents each. by addressingthe Commissioner of IEatents,

Washington, D. 6.

